Mechanical properties and first-principle calculation investigation of ZrHfNbTa series refractory high entropy alloys prepared by a combined process

Refractory high-entropy alloys (RHEAs) are widely used in aerospace engine, gas turbine high-temperature components, capacitors and catalysis. The study presents a combined process for preparing ZrHfNbTa series RHEAs. HEAs powders were prepared from metal oxide by molten salt electro-deoxidation process, and the bulk HEAs were prepared by vacuum hot-pressing sintering process. The study aimed to explore the alloying mechanism of mixed metal oxide in molten salt electro-deoxidation process to optimise the properties. The hardness and wear resistance of the bulk alloy were tested. The test results show that the hardness of ZrHfNbTa and VZrHfNbTa bulk RHEAs prepared by this process is 1251 and 1603 HV. According to the friction surface characterisation of bulk alloy, VZrHfNbTa HEA has better wear resistance than ZrHfNbTa. Based on the first-principle calculation results, the doping of V element produces a strong hybridisation of electron orbitals in RHEAs, which can effectively improve the mechanical properties of RHEAs.